Since a vinylidene fluoride-based resin has excellent weather resistance and chemical resistance and enables a melt-molding process, the vinylidene fluoride-based resin is used widely as a surface protective film for a tent of a quick-built warehouse, a canvas top of an autotruck and the like as well as a protective film for an illuminated sign, a building material and an exterior film of an automobile. In recent years, the technique of applying a laminated film made of a vinylidene fluoride-based resin and an acrylic-based resin on a surface of a plastic molded product for decoration has been gaining attention as an alternative to painting. Since a protective film or a decorative film is attached to a surface of a base material for use, such a film is required to have transparency allowing print and a pattern applied on the surface of the base material to be recognized clearly. However, the vinylidene fluoride-based resin is a crystalline resin and has a high crystallization rate, and therefore it is extremely difficult to achieve enough transparency.
A method of making a film thinner (see Patent Document 1), a method of copolymerizing another monomer to a vinylidene fluoride-based resin (see Patent Document 2), a method of mixing with a methacrylic-based resin and the like have been proposed so far. However, the films obtained by these methods cannot realize the required transparency.
Another method has been proposed, in which film shaping conditions for processing a vinylidene fluoride-based resin film (e.g., a discharge rate, a take-off rate, a residence time, a difference between a dice temperature and a coolant temperature) are controlled so as to decrease a spherocrystal radius of polyvinylidene fluoride, which is for improving the transparency (see Patent Document 4). However, it is difficult to reduce the average spherocrystal radius to be less than 0.5 μm because of the limitations of an apparatus, and therefore further improvement of the transparency has been required.
Meanwhile, a vinylidene fluoride-based resin multilayered film shaped by co-extrusion with a methacrylic-based resin composition now is gaining strong attention in the market. Specific applications therefor include a protective film laminated on various materials such as plastic, metal and wood, painting for the lamination on internal/external components of an automobile, a film used as an alternative to plating and the like, which are for preventing the deterioration of a base material and keeping the appearance, for example. Moreover, since it is expected that harmful substances discharged from a painting or a plating process will be more strictly controlled in the future from the environmental standpoint, a film is gaining attention as an alternative to them. Such a film is required to have resistance to breakage by bending (hereinafter called “break resistance”) and formability.    Patent document 1: JP S57(1982)-187248 A    Patent document 2: JP S64(1989)-8665 A    Patent document 3: JP H05(1993)-50566 A    Patent document 4: JP H06(1994)-80794 A